age related macular degeneration
DESCRIPTION
Dr. Torres gives great information on age related macular degeneration. This is a great update not only on the disease but on emerging treatments for this devastating problem.TRANSCRIPT
Age Related Macular Degeneration
Emerging Technologies
Waldemar Torres, MD, FACS
VITREO-RETINAL SURGEON
NATIVE FROM PUERTO RICO
TRAINED IN THE UNIVERSITY OF PUERTO RICO AND PONCE SCHOOL OF MEDICINE, P.R.
INTERSHIP IN STATE UNIVERSITY OF NEW YORK, BINGHAMTON, N.Y.
OPHTHALMOLOGY TRAINING AT THE ALBERT EINSTEIN COLLEGE OF MEDICINE / YESHIVA UNIVERSITY, BRONX, NY
SUB-SPECIALTY TRAINING AT SOUTH TEXAS RETINA CONSULTANTS, CORPUS CHRISTI, T.X.
MEDICAL PRIVILEGES AT: SARASOTA MEMORIAL HOSPITAL VENICE REGIONAL HOSPITAL DOCTORS HOSPITAL LAKEWOOD RANCH HOSPITAL ST. ANDREWS OUTPATIENT SURGERY CENTER
FELLOW OF THE AMERICAN COLLEGE OF SURGEONS
FELLOW OF THE AMERICAN ACADEMY OF OPHTHALMOLOGY
DIPLOMATE OF THE AMERICAN BOARD OF OPHTHALMOLOGY
MEMBER OF THE PAN AMERICAN ASSOCIATION OF OPHTHALMOLOGY
MEMBER OF THE SARASOTA MEDICAL SOCIETY
MEMBER OF THE AMERICAN MEDICAL ASSOCIATION
MEMBER OF THE FLORIDA OPHTHALMOLOGY ASSOCIATION
MEMBER OF THE HILLSBOROUGH COUNTY OPHTHALMOLOGY SOCIETY
Age-Related Macular
Degeneration Known as macular degeneration, AMD, ARMD
Approximately 15 million people in the USA have AMD
Described more than 80 years ago by Holloway TB, Verhoeff, Trans Am Opth Soc 1928
AMD is a chronic, progressive disease of the macula (central portion of retina) that destroys central vision required for reading, driving, cooking, facial recognition and other common tasks
Leading Cause of Vision
Loss AMD is the leading cause of severe vision
loss & blindness in adults over age 50 [1] in the western world
It is a global public health problem
The general consensus is that as the population grows and ages, the incidence will increase as well
The main cause of vision loss in AMD is the development of choroidal neovascularization or abnormal blood vessel growth, also known as wet AMD[1] Early Detection & Treatment of Neovascular AMD,
Bressler, JABFP 2002
AMD Types
Dry AMD Wet AMD (non-neovascular) (neovascular)
Dry AMD Accounts for the majority of AMD cases
Early stage can be very mild at first
Progressive degeneration of the RPE ( retinal pigment epithelium) and the photoreceptor loss (the light sensitive cells) and subsequent vision loss
When the patient loses most of the central vision, this central spot or degeneration is called geographic atrophy ( GA) or the end stage of it,
The progression varies between individuals, with vision loss occurring more quickly in some than in others as the tissue in the macula degenerates
Wet AMD: A Rapid Descent
TIME
Wet AMD
Blindness
Severe Vision Loss
Early Intermediate Advanced
(dry) (dry) (wet)
No Vision Loss
Today: many are
diagnosed after vision
loss
There are no good predictors
for who will develop Wet AMD
or when
Wet AMD is a debilitating disease that can result in
rapid deterioration of your central vision
Wet AMD
Imbalance of: pro-angiogenic factors that induce new blood
vessels formation angiogenic inhibitory factors that inhibit new
blood vessels formation
Excess production of VEGF (vascular endothelial growth factor)
Growth of “ abnormal blood vessels” or a choroidal neovascular membrane leading to scar formation
Wet AMD
New blood vessels grow beneath the retina
Leak blood & fluid
Damage photoreceptors ( the light sensitive cells at the back of the eye) causing permanent vision loss
Risk of Conversion to Wet AMD
43% of patients who already have wet AMD in one eye will develop wet AMD in their other eye within 5 years [1]
26.4% of patients with intermediate (dry) AMD in both eyes will develop wet AMD within 5 years [1]
6.3% of patients with intermediate (dry) AMD in one eye will develop wet AMD within 5 years [1]
[1] AREDS Report No. 11, Arch Ophthalmol, 2003
Treatment for advanced dry AMD
(GA) AMD is a complex disease with various pathologic
mechanisms
Current strategies pursued by researchers are:
New drugs that aim to prevent damage to the retina or to slow the progression of dry AMD Anti-inflammatory drugs Complement inhibition ( inhibition of a immune system
pathway) Alleviation of oxidative stress ( anti oxidants use) Reduction of accumulation of retinal toxins Enhancement of choroidal blood perfusion ( improving
circulation of retinal circulation)
Sirolimus ( Rapamycin): anti fungal and immuno-supressant agent Various phase1/2 clinical trials sponsored by
National Eye Institute has been completed Subconjunctival injection every 2 months for
dry AMD Patients with geographic atrophy Another study is using an oral dose along
with other agents for wet AMD Results will be available shortly
Fluocilonolone Acetonide Intra-vitreal implant Synthetic hydrocortisone derivative implant
inside the eye Sustained release for up to 36 months Ongoing Phase 2 trial is enrolling patients
with bilateral GA Will assess the rate of GA progression in a 2-
year span. This is a medicine secreting implant to protect
dying retinal cells
POT-4 Designed to inhibit the complement activation
system ( an immune system pathway) Intra-vitreal gel sustained release system Neutralize early AMD inflammatory
component A phase 1 study was completed and a phase
2 study is being pursued
ARC1905 ( C5 inhibitor aptamer) Prevents C5a production Eyes with dry AMD stains for C5a in
histopathological studies Possible benefit in blocking this agent A phase 1 study was recently completed Intra-vitreal injection Results not yet available
Eculizumab An antibody against C5 Currently FDA approved for paroxysmal nocturnal hemoglobinuria Phase 2 study
NT501 Genetically modified RPE intra-vitreal implant Overexpresses ciliary neurotrophic factor, a growth factor
capable of retarding cellular and functional losses in RPE and photoreceptors in neurodegenerative diseases
A phase 2 study reported visual stabilization in 96.3% of treated eyes vs. 75% of control eyes
Improvement in retinal thickness was observed as early as 4 months
It received a FDA fast track designation for the treatment of visual loss associated with GA
AL-8309A Has shown capacity to decrease oxidative
damage in animal studies of light-induced damage
Similar changes has been found in patients with dry AMD
Potential candidate Phase 2 study Topical solution for possible prevention of GA
progression as well as visual acuity changes 0ver 2-year span
Reduction of retinal toxins
Studies have shown that there is an accumulation of lipofuscin, a waste product at the leading edge of the lesion in dry AMD
It precedes the spreading of the lesion and death of retinal tissue
To slow or stop progression of GA
ACU-4429 and Fenretinide were developed to prevent the accumulation of lipofuscin
Oral doses
Phase 1 and 2 studies ongoing
Accutane is a possible candidate
Choroidal blood perfusion enhancers Reduction in choroidal blood flow is more
pronounced in patients with AMD
Alprostadil Intra-venous injection to try to improve macular
blood flow The drug failed to reach the primary outcome
MC-1101 Topical drug that has been shown to increase mean
choroidal blood flow Compelling results from a Phase 1 study have led to
a fast track FDA designation for further development of the drug
Other AMD Risk Factors
Age
Genetics
Ethnicity
Gender
Diet - modifiable
Smoking - modifiable
AREDS 2 study
The original AREDS study established that anti-oxidants, zinc supplements or a combination of both can result in a reduction in risk for AMD progression in patients at high risk
Omega 3 fatty acids in this study population given as a 1- gram dose do not appear to have any beneficial effect on preventing progression to wet AMD
Lutein and zeaxanthine , although showing no statistically significant advantage for preventing AMD progression, are reasonable substitutes for beta carotene due the increased risk of lung cancer associated with beta carotene
AREDS 2 supplement
Vitamin C 500 mg
Vitamin E 400 IU
Copper 2 mg
Zinc 80 mg
Lutein 10 mg
Zeaxanthine 2 mg
If you are taking several medications you should
consult with your physician
The idea that “ more is better” should be avoided
AREDS 2
18 % reduction in the progression to advanced AMD
22% reduction in the risk of progression to neo-vascular ( wet) AMD
30% reduction in any cataract progression
Major breakthroughs have been made in the last decade in treating the wet form of AMD
The change in near-term prognosis with 90% chance of stabilizing or increasing vision
Significant price tag of monthly intra-vitreal injections
Injection-related adverse events/ risks
Uncertainty of how long the treatment will last or when it can be stopped without risk of recurrence
Importance of Early DetectionOn Treatment for Wet AMD
Now there are treatments for wet AMD which have proven to be effective in halting the progression of wet AMD in most cases.
These treatments consist of injections in the eye.
Clinical studies have shown that these new treatments are generally more effective the earlier they begin, when the patient still has good visual acuity and the lesion is still small.
Intra-vitreal injection
It is performed in the office
Using topical anesthesia (eyedrops and gel) or a subconjunctival anesthesia (injection under the capillaries of the eye)
Under aseptic/ sterile conditions
Very low risk of infection, bleeding inside/outside the eye, cataract, retinal detachment or corneal scratch after the injection
Usually is very comfortable
Treatments for advanced wet AMD
In wet AMD, too much VEGF ( Vascular endothelial growth factor) is produced in the eye
This causes the growth of unwanted, unhealthy blood vessels
Anti-VEGF drugs block the production of VEGF and stop the development of the blood vessels
Ranibizumab ( Lucentis) Genentech, Novartis. Approved by FDA in 2006 Antibody fragment that is injected inside the eye ( intra-vitreal
injection) Has proven its benefits in several clinical trials by stabilizing or
improving the visual acuity in 95% of patients Reduces the retinal thickness and promotes sub retinal fluid
resorption A monthly intra-vitreal dose , approximately $ 2000
Bevacizumab (Avastin, Genentech) Possibly the anti-angiogenic agent most
widely used worldwide Full length antibody against VEGF Approved by the FDA for the treatment of
metastatic colorectal cancer, metastatic breast cancer and non-small cell lung cancer.
Monthly dose ( 1.25 mg) Approximately $ 17-50 month Recent infection outbreak in USA ( 2011) was
linked to a single compounding pharmacy
CATT trial
1,208 patients were randomized
injections of Lucentis vs Avastin
Monthly vs as needed injections with monthly evaluations
They were found to be equivalent on a monthly injection regimen
Aflibercept ( Eylea), Regeneron, Bayer Fusion protein of VEGFR1, VEGFR2 and IgG1
Fc fragment Every month X 3 then every 2 months Trials suggest that it is effective for longer
periods of time
Combination therapy
Targets formation of new blood vessels, inflammation and prevention of scar formation
Goal is to increase the overall efficacy and reduce the need of monthly injections and side effects by allowing the use of lower doses
Radiotherapy Selectively targets new blood vessels Attenuates the inflammatory response Decreases scar formation Initial data by different studies was encouraging decreasing the number
of current injections CABERNET study( 457 eyes)
Failed to demonstrate a visual acuity benefit The future of this treatment modality is uncertain
ORAYA therapy is a combination of anti VEGF plus a single, small dose of radiotherapy, less than 20 minutes total procedure It significantly reduced the need of multiple anti-VEGF
Photodynamic therapy and
steroids In the year 2000, PDT became the first FDA approved
treatment for wet AMD, by being the first treatment to effectively prevent vision loss
Intravenous injection of verteporfin ( light sensitive dye) that travels to the eye
Followed by a laser activation within the lesion
It causes a photochemical reaction, leading to platelet aggregation and local thrombosis ( shutting down the abnormal blood vessels)
Studies showed better visual acuity, stabilization of lesions and less retreatment studies ( PDT with Ranibizumab)
Dexamethasone and triamcinolone High rate of cataract and high ocular pressure Anti scar formation, anti inflammatory and anti new
blood vessels formation
Sunitib, FDA approved for the treatment of renal and gastrointestinal tumors
Oral dose that has shown to reduce laser-induced formation of new blood vessels in mice
Topical (eyedrops) effective decreasing formation of new blood vessels in rabbit corneas
Ongoing studies using intra-vitreal injections
CentraSight lens
Implanted into one eye
Magnifies images, projecting the bigger image onto a healthier part of the retina
Strict screening is necessary
Second Sight An implant that attaches to the outside
surface of the eye and connects to an electrode placed in the retina
A camera mounted on a pair of glasses communicates with the implant
Is in clinical trials in the USA and is already in use in Europe
Acupunture
The theory is that needles placed at certain points release energy to the liver
In traditional Chinese medicine, the liver and gallbladder are thought to control the eyes
The energy supposedly improves the function of the liver and thereby increases the blood supply to the retina
Rigorous controlled testing on a large number of patients is needed
Rheopheresis
Still not a proven therapy for dry AMD
In clinical trials it was shown to be safe but the visual results
were not conclusive
It is similar to kidney dialysis, the patient’s blood is filtered
It removes substances that accumulate in the blood as LDL
cholesterol, fibrinogen and lipoprotein A to promote an
improvement in blood flow and vascular function in the retina
and elsewhere
Microelectrical stimulation
Is being promoted as a therapy for early stages of AMD
TENS ( Transcutaneous Electrical Nerve Stimulation)
Routinely used for alleviation of pain
A low voltage current is delivered through electrodes in contact with the skin overlying key nerves around the eye
The theory is that it improves macular function and aids the removal of potentially harmful waste products
One study reported improvements of vision in patients with AMD but the study did not use controls, making the results inconclusive
Genetic testing
There are different laboratory developed genetic tests to evaluate the risk of a patient with early or intermediate AMD progressing to advanced wet AMD within certain period of time
The idea is to be able to customize an approach to monitor and treat each individual based on their reported risk scores for disease progression
This allows for a more effective monitoring of patients
Gene therapy The idea is to replace or remove a defective gene to stimulate
the cell not to die and function properly again
Different abnormal genes related to AMD have been identified
The new gene is introduced into the retina via a virus (vector) , which deliver the genetic information for the rest of the patient’s life
Gene replacement therapy
Studies using animal models are now underway
Several companies are at the forefront of research into the use of gene therapy for wet AMD. These include Genzyme; Avalanche Biotechnologies, working with the Lions Eye Institute of Perth, Australia; and Oxford BioMedica, in partnership with Sanofi.
Macular degeneration and
stem cells On January 3, 2011, Advanced Cell Technology received a
FDA approval to treat advanced dry AMD using retinal pigment cells (RPE) from human embryonic stem cells
Uses a proprietary technique to extract a single cell from a young embryo allowing the rest to remain intact and develop normally
Phase1/2 study to determine the safety of RPE sub retinal implantation
UCLA, Wills Eye and Ear infirmary, Bascom Palmer Eye Institute and Massachusetts Eye and Ear.
July 9, 2012, FDA approved an increase of stem cell dosage to 100,000 RPE cells derived from human embryonic stem cells
June, 2012, a total of 16 patients started transplantation with Human Central nervous system stem cells ( non embryonic)
Study criteria: 50 years old or older Have no prior or current choroidal neovascularization Specific degree and extend of geographic atrophy No Diabetic retinopathy, cancer, glaucoma or autoimmune
disease
Allogenic cells ( another source other than the patient) and will receive immunosuppressive drugs X 3 months
4 patients have been transplanted with a single dose of 200,000 HuCNS-SC
Retina Foundation of the Southwest, Dallas, TX and Byers Eyes Inst., Stanford, Palo Alto, CA
January 2013 update: “No significant safety issues with human
embryonic stem cells in any of the 18 patients” “ 2 patients that has been treated showed some
signs of visual improvement and those gains in visual acuity have persisted for 18 months”
“ no signs of tumorigenicity, apparent rejection, ectopic tissue formation”
August 8, 2013 - The RIKEN Institute in Japan has started a clinical study for a wet AMD treatment derived from induced pluripotent stem cells (iPSC) — mature cells that have been genetically reprogrammed to a stem cell-like state
Unfortunately, many wet AMD patients suffer irreversible vision loss by the time they are diagnosed.(3)
Because wet AMD progresses rapidly, at a rate of 18-20 µ per day (4), frequent monitoring is critical.
It is impractical for patients to visit their eye doctor as frequently as needed for earliest detection.
The most effective solution for early detection is home-based monitoring in addition to routine eye exams.
(3) Olsen, Ophthalmology 2004(4) Vander, Ophthalmology 1989
Importance of Early Detection
Amsler gridTo test each eye individually to
determine if there are any squiggly lines
or distortions in the grid
Normal Fundus Fluid and Lipid Hemorrhage
20/25 20/30 20/100
Therapeutic
window
By the time you notice symptoms or Amsler Grid changes
irreversible vision loss often has already occurred
Our brain will correct the signals received if assumes incomplete or inaccurate, making it extremely difficult for AMD patients to notice that something has gone wrong in their
retina until damage is profound
Early Detection of AMD
• The first FDA cleared home based telemonitoring system for AMD• Personalized patient monitoring, between physician exams• Designed for early detection, before noticeable symptoms & vision
loss• Preferential Hyperacuity Perimetry
• Demonstrated sensitivity, specificity• Robust normative database• Quantifies changes in metamorphopsia
The ForeseeHome was designed specifically for easy operation by AMD patients. It has received numerous awards for product design and its user friendly interface.
So what do we have to do?Do not smoke
Control your blood pressureGet regular physical activity such walking 30 minutes daily
Eat a variety of colors of fruits and vegetablesConsider natural sources of omega-3 fatty acids such tuna and wild
salmonTake AREDS 2 supplements
Protect you eyes with 100 % UV protection sun glassesUse a visor or a hat to block out more of the sun’s rays
www.geteyesmart.org